Lender asks us to sign the final loan docs one week before closi

Please help:

The closing date is 11/28/11 and lender wants us to sign the final loan docs on 11/21, is it normal? The property is currently tenant occupied, seller needs to transfer the property vacant according to the purchase agreement. I won't be able to verify the vacancy until the final walk-through on 11/23, I am ready to walk away if the tenant doesn't vacate by then.

My question is --should I sign  the final loan docs before the verification of vacancy? Should the loan docs be signed the last day of closing? I am confused, thanks to all for your help!